The patient is a 15-year-old female who initially presented to our hospital at the age of 6 with complaints of tachycardia. However, no significant abnormalities were identified, and she was subsequently placed under observation. At the age of 7, the patient developed symptoms including headache, chest pain, and absent pulses, accompanied by a pronounced inflammatory response. A thorough diagnostic evaluation was performed, which led to the diagnosis of Takayasu’s arteritis. At that time, computed tomography (CT) imaging revealed a fusiform aortic aneurysm with a maximum short axis diameter of 34 mm, extending from the ascending aorta to the proximal aortic arch. Under vigilant monitoring, by the age of 15, the maximum short diameter had increased to 45 mm, demonstrating progressive enlargement over time. Following a multidisciplinary discussion of treatment options in a heart team conference, it was determined that surgical intervention was warranted. Given that the patient was receiving maintenance therapy for a relapse of arteritis, the dose of prednisolone was reduced to 4 mg prior to performing an ascending partial arch aortic replacement. The postoperative course was uneventful, and the patient was discharged on postoperative day 13. She continues to receive maintenance therapy and undergoes regular CT scans at the outpatient clinic. Childhood-onset Takayasu’s arteritis is exceedingly rare, but with timely surgical intervention and sustained disease management, an improved long-term prognosis can be anticipated.